NK/K F47|NK F47 STEEL PLATE

NK F47 steel plate, also written as KF47, K F47, ClassNK F47, NK Grade F47 or market names such as FH46 / FQ47, is the extra-high-strength hull structural steel of ClassNK (Nippon Kaiji Kyokai) Rules for the Survey and Construction of Steel Ships (IACS UR W16 extra-high-strength family) with 460 MPa minimum yield, 570-720 MPa tensile strength and Charpy V-notch toughness at -60°C [-76°F]. In the grade name, "F" is the toughness class, and "47" is the site strength label for about 460 MPa yield (ABS FQ47 family). Gangsteel, a steel plate exporter, supplies NK F47 / KF47 plates cut to size for shipbuilding, offshore platforms and marine structures.

Data source: Per IACS UR W16 (extra-high-strength hull structural steel) as adopted in ClassNK hull structural steel rules, cross-checked with LR FH46 / ABS FQ47 sibling pages on gangsteel.net. Official mill/certificate grade is typically KF47 (K F47); NK F47 names the same class on this site. Verify the current ClassNK edition before ordering.

NK F47 / KF47 Chemical Composition (Heat Analysis)

 

Element	C	Mn	Si	P	S	Al (acid sol.)
NK F47, %	0.18 max	1.60 max	0.10-0.55	0.025 max	0.025 max	0.015 min
Element	N	Nb	V	Ti	B	Notes
NK F47, %	0.020 max	0.02-0.05	0.04-0.10	0.02 max	0.005 max	Ni/Cu/Cr/Mo per delivery condition (N/TM/QT) in UR W16

Per IACS UR W16 / ClassNK extra-high-strength rules. Exact maxima for Ni, Cu, Cr and Mo depend on delivery condition (N/NR, TM or QT). Carbon equivalent / CET / Pcm limits apply by thickness and condition; confirm on the mill certificate and current rule edition.

Product Analysis (Check Analysis)

 

When product analysis is required, apply ASTM A6/A6M Table A permitted variations to the heat limits unless the element is min-only or not listed in Table A.

Element	Heat analysis limit	Product analysis (heat ± A6)
C	0.18 max	0.22 max
Mn	1.60 max	see A6 Table A vs heat upper limit
Si	0.10-0.55	0.05–0.61 (approx. A6)
P	0.025 max	0.035 max
S	0.025 max	0.035 max
Al (acid sol.)	0.015 min	no A6 Table A tolerance; product value not tabulated
N	0.020 max	0.025 max (typical A6 +0.005)
Nb	0.02-0.05	0.010–0.060
V	0.04-0.10	0.030–0.110
Ti	0.02 max	0.03 max
B	0.005 max	product analysis often not applicable

Product analysis applies only when specified; for a range, results may not vary both above and below it.

NK F47 / KF47 Mechanical Properties

 

Grade	Yield strength, min	Tensile strength	Elongation, min
NK F47 / KF47	460 MPa [67 ksi]	570-720 MPa [83-104 ksi]	17%

Per IACS UR W16 / ClassNK rules (common t≤50 mm values). Yield may step down for thicker plates per UR W16; confirm thickness-dependent values on the order.

Charpy V-Notch Impact Requirements (-60°C [-76°F])

 

Thickness	Test temperature	Longitudinal, avg min	Transverse, avg min
t≤50 mm	-60°C [-76°F]	46 J	31 J
50<t≤70 mm	-60°C [-76°F]	46 J	31 J
70<t≤100 mm	-60°C [-76°F]	46 J	31 J

Per IACS UR W16 / ClassNK extra-high-strength practice. Average of three full-size specimens; transverse values apply when required. Thicker plates by agreement.

Delivery Condition and Deoxidation

Deoxidation: Killed, fine-grain practice. Delivery condition: typically TMCP or QT for extra-high-strength plates; N/NR may apply at lower extra-high levels per rules. F-class (K F47 / FQ47) grades are supplied normalized or TMCP (often with Ni alloying for -60°C toughness); as-rolled delivery is not permitted. Optional extras: UT, Z15/Z25/Z35, ClassNK survey.

Thickness Coverage

Extra-high-strength NK A/D/E/F 43/47/51/56/63/70 plates (about 420-690 MPa family) are commonly supplied from about 6 mm to 100 mm thick (thicker by agreement under UR W16). Width 1500-4000 mm and length 6000-18000 mm are typical.

Equivalent Steel Grades of NK F47

 

Society / Standard	Equivalent grade
NK (ClassNK)	NK F47 / KF47 (LR FH46 / ABS FQ47)
LR (Lloyd's Register)	LR FH46 steel plate
ABS	ABS FQ47 steel plate
CCS	CCS F460 steel plate
DNV	DNV F460 steel plate
BV	BV F460 steel plate
KR	KR F47 steel plate
RINA	RINA F460 steel plate

IACS societies align extra-high-strength hull grades under UR W16; naming differs (NK F47, LR FH46, ABS FQ47, DNV F460). Dual certification is common when ordered that way.

FAQ about NK F47 / KF47 Steel Plate

What is NK F47 (KF47) steel plate?

It is an extra-high-strength hull structural steel under ClassNK Rules (IACS UR W16 extra-high-strength family), with 460 MPa minimum yield, 570-720 MPa tensile strength and Charpy toughness at -60°C [-76°F].

What does NK F47 / KF47 stand for?

NK (ClassNK) is Nippon Kaiji Kyokai. The K prefix (KF47) is the ClassNK mill designation. The letter F is the toughness class (Charpy at -60°C [-76°F]), and 47 is the yield-strength level in MPa. Market/LR naming often uses FH46; ABS often uses FQ47. This site uses ABS-like numbers (A43…A70), corresponding to about 460 MPa (ABS FQ47 / LR FH46 / DNV F460 family); there are no A420 paths under /nk/.

What is the yield strength of NK F47?

Minimum 460 MPa (67 ksi), tensile 570-720 MPa (83-104 ksi), elongation about 17% min (for the common thickness range).

What is the impact test temperature for NK F47 / KF47?

Charpy V-notch at -60°C [-76°F]. Typical longitudinal average minimum is 46 J (transverse 31 J) for the tabulated thickness range on this grade page.

What is the difference between NK A47, D47, E47 and F47?

Same 460 MPa strength class. Toughness class differs: A at 0°C, D at -20°C, E at -40°C, F at -60°C. Chemistry (C, P, S, Mn) is tightened for colder classes.

How does NK F47 differ from higher-strength NK A40?

NK A40 is UR W11 higher-strength (390 MPa). NK F47 is UR W16 extra-high-strength (460 MPa) with different chemistry and delivery practice (often TM/QT).

Is NK F47 the same as LR FH46 or ABS FQ47?

They are IACS counterparts in the extra-high-strength family; exact chemistry/delivery options differ by society edition. Dual certification is available when surveys are arranged.

Is NK F47 weldable?

Weldable with approved procedures for extra-high-strength ship steel. Preheat, heat input and consumable matching are critical; follow the mill WPS and ClassNK welding requirements.

What heat treatment is required for NK F47?

Extra-high-strength grades are typically delivered TMCP or quenched and tempered (QT), sometimes normalized/normalized-rolled depending on strength level and thickness. F-class (K F47 / FQ47) grades are supplied normalized or TMCP (often with Ni alloying for -60°C toughness); as-rolled delivery is not permitted. Optional extras: UT, Z15/Z25/Z35, ClassNK survey.

What thickness is available for NK F47?

Common supply is about 6-100 mm (thicker by agreement under UR W16 / ClassNK rules), 1500-4000 mm wide and 6000-18000 mm long.

Other NK Steel Plate Grades

NK Grade A steel plate | NK Grade B steel plate | NK Grade D steel plate | NK Grade E steel plate | NK A32 steel plate | NK A36 steel plate | NK A40 steel plate | NK D32 steel plate | NK D36 steel plate | NK D40 steel plate | NK E32 steel plate | NK E36 steel plate | NK E40 steel plate | NK F32 steel plate | NK F36 steel plate | NK F40 steel plate | NK A43 steel plate | NK A47 steel plate | NK A51 steel plate | NK A56 steel plate | NK A63 steel plate | NK A70 steel plate | NK D43 steel plate | NK D47 steel plate | NK D51 steel plate | NK D56 steel plate | NK D63 steel plate | NK D70 steel plate | NK E43 steel plate | NK E47 steel plate | NK E51 steel plate | NK E56 steel plate | NK E63 steel plate | NK E70 steel plate | NK F43 steel plate | NK F51 steel plate | NK F56 steel plate | NK F63 steel plate | NK F70 steel plate

Equivalent Class Society Grades

NK F47 / KF47 corresponds to extra-high-strength counterparts under other IACS societies (LR FH46, ABS FQ47, etc.): LR FH46 steel plate, ABS FQ47 steel plate, CCS F460 steel plate, DNV F460 steel plate, BV F460 steel plate, KR F47 steel plate, RINA F460 steel plate.